Avalanche Forecast
Issued: Nov 29th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Deep Persistent Slabs.
Ian Jackson,
Avalanche Control is planned for the Sunshine Road on Nov. 30th. No access to Mt Bourgeau or Eagle Mountain zones.
Summary
Weather Forecast
Temperatures will cool Mon night, but then warming as the next storm arrives. Winds will rise to strong to extreme from the west and freezing levels are forecasted to be in the 2000m range. Models are forecasting ~20 cm by end of Tues, ~ 60 cm by end of Wed, and another ~ 10 cm as the system passes and cools on Thurs. Rain in valley bottoms.
Snowpack Summary
30-60 cm of snow in the last storm is reacting as a storm slab in alpine and treeline terrain. The Nov 15 crust is below this and present below 2100 m. The Nov 5 crust/facet layer exists near the ground. Snowpack depths at tree-line average 80-110 cm. Lower elevation snow (below ~ 1500 m ) is rain- soaked.
Avalanche Summary
Natural activity to size 3 as a result of the weekends storm was observed on Monday. Results from avalanche control in Kootenay showed touchy storm slabs at treeline and in the alpine with higher elevation avalanches stepping down to the deep persistent layer. At lower elevations, (below ~ 1700m), these were entraining loose wet snow.
Confidence
Timing, track, or intensity of incoming weather system is uncertain
Problems
Storm Slabs
Recent new snow has created storm slabs that have been failing naturally and with explosives. The incoming storm will add load and make this worse. Treat all avalanche terrain with caution.
- If triggered the storm slabs may step down to deeper layers resulting in large avalanches.
- Watch for surface cracking and stiffer surface layers of snow. Avoid wind loaded terrain.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
With a significant new snow load we expect to see larger and more frequent avalanches occur on the basal crust and facets. These avalanches have sporadically been running full path so minimize your exposure to overhead hazards.
- Be aware of the potential for full depth avalanches due to deeply buried weak layers.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Nov 30th, 2021 4:00PM
